What may add the arrow of time is the second law of thermodynamics: a statistical evolution of a system is not symmetric.
I wonder now how a violation of causality could either circumvent of contradict the second law.
To add something substantive, my question to the thread is: anyone here have thoughts on how these questions relate to McTaggart's unreality of time? https://en.wikipedia.org/wiki/A_series_and_B_series
Moving energy around through time may serve to increase entropy overall.
You can't be a scientific american if you keep using the science words bad.
It's like cargo culting science: Use these words correctly if you want to seem to know what you're talking about!
But anyone who actually knows what they are talking about would use these words correctly, or at least not be mistaken about their meaning.
So this article is teaching people that have no idea what they're talking about, how to sound like they do.
Maybe it's time we start using another language for science. Clearly it's confusing the Scientific Americans.
At some point a particle pops up into existence in B, increasing B's pressure.
Some time later, a particle from A disappears, decreasing A's pressure.
This pressure differential would cause flow from B to A through X.
Alternatively, a particle randomly disappears from B, decreasing B's pressure.
Some time later, a particle appears in A, increasing A's pressure.
This would cause flow from A to B through X.
The more particles that cross from A to B via Y, increasing B's pressure, the more likely it is for particles to pass from B to A via Y, keeping these two effects equal.
These two pressure differentials would cancel out for large numbers of particles.
You've essentially just hooked up the system to itself, but at a future point in time. Unless the overall pressure of the system is changing, there is nothing to induce the flow. If you are increasing the pressure, valve Y is essentially just a standard one-way valve.
If we perceived the world through sonar then causality would be violated by anything supersonic. If you were shot then you'd feel the bullet first and then "see" it moving back into the gun.
AFAICS if information can travel at >c, then physical objects traveling at >c doesn't violate causality
http://www.physicsmatt.com/blog/2016/8/25/why-ftl-implies-ti...
The sonar example works only if everything is traveling in roughly the same frame of reference. You're not accounting for relativity and its effects on space and time in your analogy.
If you draw a tachyon on a spacetime diagram going faster than the speed of light, you can create situations where the tachyon travels back in time for certain observers.
> AFAICS if information can travel at >c, then physical objects traveling at >c doesn't violate causality
If information can travel faster than c, then you can create situations where it's also violating causality.
It's clear that your point of view matters in physics, but it's also clear that I have no idea what a "point of view" means in this context.
If I am stationary and measuring you flying past me in a relativistic train, I would measure you in a coordinate grid say, centered on myself. You may be watching me from your train and doing the same, but from a reference grid stationary with respect to you but moving with respect to me. Even if we both agreed on identical measures ahead of time, your measurement of me from your reference frame and mine of you from my reference will be off from a measurement we do ahead of time in the same reference frame as a calibration. However, that difference comes out in the wash through the magic of the Lorentz Transformation. Using the Lorentz Transformation, I should be able to negotiate transforming a measurement I do of you in my own reference frame to what it would look like from yours and you should be able to transform yours to mine, through which we'd both come to the same numbersassuming we're in spacetime that shares the same general degree of curvature (same gravity). This can even be generalized to arbitrary degrees of spacetime curvature. I.e. if your relativistic train is racing past a black hole with a near tangent intersect, and I'm stationary with reference to the black hole centric reference frame but further out in the system, as you blast through the high curvature part of your trip your clock may seem to de-sync from mine. This too, however, can be mitigated through copious amounts of math I don't get for more than half an hour after looking away from a text book. I just know if I ever have a problem to solve that involves hitting that book again, I have either made some terrible or awesome decisions in my life.
You need to impose additional constraints on the theory (e.g., real mass conditions) to get rid of them.
(Again I may have misunderstood, but the frame of the CMB sometimes gets talked about as if it might be a preferred frame).
If light is just information, wouldn’t it just be a matter of seemingly getting something very fast?
Everytime I think I get it, I don’t!